Variable pitch tapeless format control system for line printers

ABSTRACT

A tapeless format control system for a line printer is provided which will control the pitch between printed lines on various length web paper forms. The system includes a stepping motor for driving a paper advance mechanism, a manually operated shift mechanism for selecting the desired one of a plurality of form lengths, and a plurality of photo cells and light sensing devices associated with the stepping motor, the paper advance mechanism and the form length selecting mechanism, said cells and sensors cooperating with logic circuitry in response to two different types of spacing instructions received from a central processor to provide a wide variety of printing formats on a variety of form sizes to thereby assure optimized flexibility in printing with the line printer.

United States Patent Hotfman VARIABLE PITCH TAPELESS FORMAT CONTROL SYSTEM FOR LINE PRINTERS [75] Inventor: Paul R. Hoffman, Farmington,

Mich.

[73] Assignee: Burroughs Corporation, Detroit.

Mich.

[22] Filed: June 1, 1973 [21] Appl. No.: 366,122

[52] 0.8. CI. 197/133 R; 74/348 [51] Int. Cl B4lj 15/00 [58] Field of Search 197/84 R, 133 R; 74/191, 74/337, 337.5, 341, 348

[56] References Cited UNITED STATES PATENTS 284,476 9/1883 Perrett 74/348 774,910 11/1904 Crawford....... .1 74/348 X 882,968 3/1908 Ruck 74/348 912,736 2/1909 Ruck r r 74/348 X 1,206,043 ll/l916 Slonecker 74/348 2,842,246 7/1958 Furman et a1... 197/133 R 3,123,195 3/1964 Hewitt et a1. 197/133 R 3,323,700 6/1967 Epstein et a1. 197/133 R UX 3,346,086 10/1967 Cralle et a1. 197/84 R 3,499,516 3/1970 Schaaf i 197/133 R 3,502,190 3/1970 Smith 197/133 R 3,557.929 l/l97l Schaaf 197/133 R 3,643,039 2/1972 Barcomb et al 197/133 R 3,656,041 4/1972 Bonzano 197/133 R June 10, 1975 3,761,000 9/1973 Hagstrom 197/133 R X OTHER PUBLICATIONS IBM Technical Disclosure Bulletin, Tapeless Carriage Control," Kerr et 211., Vol. 13, No. 3, August 1970, pp. 657-658.

IBM Technical Disclosure Bulletin, "Overcoming Forms Length Limitations in Line Printers," Brown, Vol. 15, No. 4, September 1972, pp. 1155-1157.

Primary ExaminerEmest T. Wright, Jr. Attorney, Agent, or Firm-Edwin W. Uren; Edward G. Fiorito; Paul W Fish [57] ABSTRACT A tapeless format control system for a line printer is provided which will control the pitch between printed lines on various length web paper forms. The system includes a stepping motor for driving a paper advance mechanism, a manually operated shift mechanism for selecting the desired one of a plurality of form lengths, and a plurality of photo cells and light sensing devices associated with the stepping motor, the paper advance mechanism and the form length selecting mechanism, said cells and sensors cooperating with logic circuitry in response to two different types of spacing instructions received from a central processor to provide a wide variety of printing formats on a variety of form sizes to thereby assure optimized flexibility in printing with the line printer.

25 Claims, 6 Drawing Figures PATENTEDJUH 10 I975 888; 340

SHEET 3 T'- o o -,M u

15"- g 0 l O VARIABLE PITCH TAPELESS FORMAT CONTROL SYSTEM FOR LINE PRINTERS FIELD OF THE INVENTION The invention relates generally to a format control system for line printers and more particularly to a tapeless format control system for controlling the advancement of web paper in a line printer.

BACKGROUND OF THE INVENTION Many prior art printing systems make use of pre punched paper tape loops to control the spacing and arrangement of printed information on paper forms. Such loops are generally provided with rows and columns of machine readable apertures which represent spacing and formatting control instructions, the tapes being selectively and individually installable in tape sensing devices in the printer where they are advanced in synchronism with the advancement of the web paper. During this synchronized advancement of the tape loops, the aperture therein are sensed by sensing means, whereupon pulses resulting therefrom are transmitted through appropriate circuitry to the web paper advancing means of the printer, the web paper advancing means being thereby controlled from a starting and stopping standpoint to produce the desired arrangement of the printed information on the web paper forms. The control instructions represented by the apertures in the tape loops are generally combined with line selection instructions transmitted to the printer from a central processor or other extraneous control device.

Format control tapes of the kind commonly used in prior art line printers, and in format control apparatus forming a part thereof, have generally been characterized by two different categories of problems, a first category involving the operational characteristics of the apparatus used for sensing and advancing the tapes, and the second category involving the condition and storage requirements of the tapes themselves. Prominent among the first category of problems are the inertial tendencies of prior art tape advancing apparatus, such tendencies frequently causing the start-up or stopping motion of the tape to either lag behind or to run ahead of the starting or stopping of web paper motion, thereby giving rise to the disruption of the required synchronization between the tape and the web paper. Included in the second category of problems, involving the tapes themselves, are the need of maintaining space-taking files for storing a plurality of tapes that are not in active usage, the tendency of the tapes to become worn and dilapidated through excessive use or misuse, and the likelihood of error in either punchably producing the tapes or in effecting installation thereof in the tape sensing and advancing apparatus.

SUMMARY OF THE INVENTION It is accordingly an object of the present invention to provide an improved format control system for use in high speed line printers, such system efiectively eliminating the operational prior art problems that have attended the use of paper tape loops.

It is another object of the invention to provide an improved format control system that is operable independently of format control tapes, thereby relieving the need of space-taking tiles for storing such tapes, and relieving also the extreme care that has been required of operators in effecting proper installation of such tapes in the printers.

Still another object of the invention is to provide an improved format control system wherein the desired formatting of the printed information may be achieved without undue attention and inconvenience on the part of the operator.

Yet another object of the present invention is to provide a format control system that is completely reliable in operation and ideally flexible in its ability to produce the desired formatting of printed information on any desired form length.

The present invention is directed to a tapeless format control systetm for use in line printers, such system including a stepping motor for incrementally advancing the web paper, means for selectively determining the length of the paper form upon which the printed information is to be arranged, a plurality of pulse generating means for identifying each increment of motion of the stepping motor, each increment of advancement of the web paper, and the passage of each unit of selected form length past the print station, means also being in cluded for receiving and storing skip and line advance spacing instructions from a central processor, and for controllably coordinating such extraneous instructions with said plurality of identifying pulses such that each line of information printed on the selected length form is properly spaced from the preceding lines and all of the lines of printed information conform to the preselected format represented by the extraneous instructions.

In the preferred embodiment of the invention, the aforementioned means for selectively determining the length of the form upon which the printed information is to be arranged, is comprised of a conical stack of variously diametered gears, and settable means for coupling a selected gear of the stack with the incrementally driven paper-advancing shaft, such that the pulse generating means associated with form length is rendered effective for generating a pulse when each unit of form length corresponding to the selected gear has been moved into cooperating relationship relative to the print station.

BRIEF DESCRIPTION OF THE DRAWING These and other objects and advantages of the invention will become apparent from the following description when read in conjunction with the accompanying drawing figures, in which:

FIG. 1 is a partial perspective view showing various of the elements of the inventive format control system in association with web paper advancing means in a line printer;

FIG. 2 is an elevational view of various of the elements shown in FIG. 1;

FIG. 3 is a view taken in the direction of the arrow 3 of FIG. 2;

FIG. 4 is a schematic block diagram illustrating the logic circuitry of the inventive format control system;

FIG. 5 is a plan view of the adjustable dials shown in FIG. 1; and

FIG. 6 is a view of a portion of the continuous web paper used in the line printer, separable form sheets thereof being represented by perforated lines and representative printing lines thereon being identified by a plurality of broken lines.

DESCRIPTION OF THE PREFERRED EMBODIMENT As previously indicated, the inventive tapeless format control system is comprised of a stepping motor for incrementally advancing the web paper, means for selectively determining the length of the paper form upon which the printed information is to be arranged, a plurality of pulse generating means for identifying each increment of rotational motion of the stepping motor, each increment of advancement of the web paper, and the passage of each unit of selected form length past the print station, means for receiving and storing externally originated skip and line advance spacing instructions, and means for controllably coordinating the skip and line advance instructions with the plurality of identifying pulses such that each line of information printed on the selected form length is properly spaced from the preceding lines. Each of these broadly defined elements of the inventive format control system will be hereinafter described from a structural and functional standpoint, with reference to the accompanying drawing figures.

As illustrated in FIGS. 1 and 4, a stepping motor 16 fixed to the framework (not shown) of a line printer is provided with an incrementally rotatable motor shaft 20 to the outermost extremities of which are fixed a photocommutator disk 18 disposed in cooperating relationship with a sensing device 22, and a toothed pulley 21 which is coupled to a predeterminately larger toothed pulley 23 by means of a belt 14. The pulley 23 is fixed to an extremity of a paper advance shaft 12 which is provided with fixed and spaced-apart sprockets 10, the extending teeth of the sprockets being cooperably engageable with perforations 13 arranged along the outermost edges of the web paper 24 to thereby advance the web paper 24 to a printing position of the line printer as represented by an impact bar 19 shown in FIG. 1.

The previously mentioned means for selectively determining the length of the paper form upon which the printed information is to be arranged is comprised of a conically configured stack of variously diametered gears generally indicated at 30 in FIGS. 1 and 2, such gears 30 being fixed to a shaft 32 that is journaled in a frame member 34 (FIG. 2). In the preferred embodiment of the invention, the conical stack of gears 30 is comprised of a total of 18 gears ranging in toothed circumference from l7 to 34 teeth, each gear having one additional peripheral tooth over its smaller diametered adjoining gear, the smallest diametered l7-toothed gear representing an 8% inch form length and the largest diametered 34-toothed gear representing a 17 inch form length, each of the gears therebetween representing different form lengths of half inch differential. The conical stack of variously diametered gears 30 is operatively coupled to the paper advance shaft 12 by means of an elongated wide-faced gear 28 fixed to the rightmost extremity of the shaft 12, and a rotatably and translatably supported idler gear 44, rotation of the paper advance shaft 12 by the stepping motor 16 thereby providing rotational movement to the idler gear 44 and to the conical gear stack 30. Selection of a given form length within the previously defined range of from 8% inches to l7 inches is accomplished by manually rotating a dial 41 to bring the indication mark corresponding to the given form length (FIG. 5) into alignment with a single mark on a cursor 33', rotation of the dial 41 being effective to rotate a supporting shaft 59 and a pair of bevel gears 55, 53 (FIG. 1), the bevel gear 53 being fixed to a suitably supported and normally disposed short shaft 59' to the other extremity of which is fixed in a pinion gear 52. It can be seen from FIG. 1 that the pinion gear 52 is engaged with the linearly arranged teeth of a rack 46, the rack 46 being translatable on a supporting and retaining base member 48. The rack 46 is provided on its innermost extremity with a short mounting shaft (not shown) upon which the idler gear 44 is rotatably mounted. It can thus be seen that rotation of the dial 41 will serve to effectuate a corresponding translation of the rack 46, by means of the shafts 59 and 59', the fixed gears 55-53 and the pinion gear 52, to thereby engage the coupling gear 44 with the individual gear of the stack 30 that corresponds to the indexed form length.

As may be suggested by the hereinafter described detenting means illustrated in FIGS. 2 and 3, the form selection dial 41 may be manually rotated only after the conical gear stack 30 has been returned to a home position wherein corresponding peripheral teeth of the various gears in the stack 30 are aligned to enable translation of the coupling gear 44. This home position of the gear stack 30 is defined by the central coincidence of a line mark 29 on a home positioning dial 36 relative to a pair of marks 31 on a cursor 33, as best shown in FIG. 5. FIGS. 1 and 3 are illustrative of the detenting means effective for preventing manual rotation of the form selection dial 41 when the gear stack 30 is displaced from its above defined home position. This detenting means is comprised of a locking wheel 38 fixed to the shaft 32, a peripherally notched or toothed detent wheel 54 fixed to the shaft 59, and a rockably supported and biased detent arm 42 interposed between the wheels 38 and 54. The locking wheel 38 is provided with a concave recess 40 which is conformably aligned with a curved portion 57 of the detent arm 42 only when the dial 36 and gear stack 30 are located in their home positions, such conformable alignment of the recess 40 permitting a spring 58 to rock the detent arm 42 such that a projection 56 thereof is displaced from its engageable locking relationship with the wheel 54. When the dial 36 and gear stack 30 are displaced from their home positions, as when operatively rotated by the wide-faced gear 28 and idler gear 44, the raised concentric surface of the locking wheel 38 serves to depressably hold the detent arm 42 and the projection 56 thereof in engageable locking relationship relative to the notches or teeth in the detent wheel 54, against the bias of the spring 58.

In accordance with the above description, the selection of a given form length may be accomplished by first rotating the dial 36 to its home position, to thereby align corresponding peripheral teeth of the individual gears of the gear stack 30 and to enable the spring 58 to disengage the detent arm 42 from the wheel 54, and by then rotating the form selection dial 41 to a position corresponding to the desired fonn length, the idler gear 44 being thereby translated into engaged relationship with the individual gear of the stack 30 that corresponds to the desired form length. It is to be noted that a disconnect clutch 35 (FIG. 1) is provided intermediate the paper advance shaft 12 and the wide-faced gear 28 to permit rotation of the dial 36 and gear stack 30 without disturbing the position of the shaft 12 or the web paper 24.

The aforementioned plurality of pulse generating means forming a part of the present invention includes the multi-slotted photocommutator disk 18 fixed to the motor shaft 20 and its associated sensing device 22, a single-slotted disk 37 fixed to the innermost extremity of the shaft 32 of the previously defined form length selecting means, along with its associated sensing device 39, and a multi-slotted disk 26 fixed to the paper advance shaft 12 intermediate the disconnect clutch 35 and the wide-faced gear 28, the disk 26 being associated with a sensing device 25. Each of the sensing devices 22, 25 and 39 is provided with at least one wellknown light emitting element 17 disposed on one side of its associated slotted disk 18, 26 or 37, as best shown in FIG. 1, and at least one light sensitive switch or photo cell 27 disposed on the other side of said disk as best illustrated in FIG. 4, such elements being effective for pulsably sensing the passage of a slot therebetween. As best shown in FIG. 4, the multi-slotted photocommutator disk 18, identified hereinafter as the motor step disk 18, is provided with eight equally spacedapart radial slots, and the multi-slotted disk 26, identified hereinafter as the field mark disk 26, is provided with 16 equally spaced-apart radial slots. ln the preferred embodiment of the invention, each of the eight radial slots of the motor step disk 18 is operatively sensed by three light emitting members 17 and associated light sensitive switches or photocells 27 of the sensing device 22, thereby providing for the generation of 24 pulses for each revolution of the motor shaft 20, each of such pulses representing an incremental step of motor shaft 20 movement equal to a angular displacement thereof. The predetermined relative diameters of the motor shaft pulley 21 and the pulley 23 of the shaft 12 are such that each 15 increment or step of motor shaft movement will produce a 1 120 inch of web paper 24 advancing movement, a complete revolution of the motor shaft 20 thereby producing oneftfth inch of paper 24 advancement. ln the preferred embodiment, also, the diameters of the sprockets 10 on the paper advance shaft 12 have been so predetermined that one revolution of the shaft 12 will produce 8 inches of paper 24 advancement. it can thus be seen that each of the 16 pulses generated during each revolution of the paper advance shaft 12, by reason of the passage of the 16 slots of the field mark disk 26 between the light emitting element 17 and light sensitive switch 27 of the sensing device 25, will serve to represent and to identify a 1: inch incremental advancement of the web paper 24. It will also be apparent from FIG. 1 that the single-slotted forms index disk 37 will generate a pulse upon each occurrence of the gear stack 30's advanceable return to its home position, such pulse, produced by the light emitting element 17 and light sensitive switch 27 of the sensing device 39, accordingly representing and identifying the advancement of each unit of the selected form length.

The previously mentioned means for receiving and storing skip and line advance spacing instructions from a central processor is comprised of the shift register 64 shown in FIG. 4, such register 64 consisting of a fivedigit field advance instruction portion and a four-digit line advance instruction portion, the five digits of the field instruction portion representing the binary decimal digits 1, 2, 4, 8 and 16, and the four digits of the line instruction portion representing the binary decimal digits 1, 2, 4 and 8. It will thus be seen that the field instruction portion of the register 64 will be effective to receive and store 32 separate codes to provide for k inch incremental advancements of the web paper 24, and that the line instruction portion will be effective to receive and store 16 separate codes to provide for various ll120 inch incremental advancements of the paper 24, the latter incremental advancements being explained hereinafter in connection with the previously mentioned broadly defined means for controllably coordinating the skip and line advance instructions with the plurality of identifying pulses.

FIG. 4 is illustrative of the means for controllably coordinating the skip and line advance instructions stored in the register 64 with the plurality of identifying pulses generated by the forms index disk 37, the field mark disk 26 and the motor step disk 18. A line decoder is coupled to the line instruction portion of the register 64 by lines 72, and coupled also to an encoder 94 by a plurality of lines 92. It is the function of the line decoder 90 to interpret and give meaning to the 16 possible codes received and stored in the line instruction portion of the register 64. The following table is suggestive of how these 16 codes might be interpreted:

Decoded Code instruction 0000 No advance 0001 Single space lO-per-inch (S10) 0010 Single space S-per-inch (S8) 001 1 Single space 6-per-inch (S6) 0100 Double space IO-per-inch (D10) 0101 Double space S-per-inch (D8) 01 10 Double space 6-per-inch (D6) 01H Triple space 10-per-inch (T10) 1000 Triple space 8-per-inch (T8) 1001 Triple space 6-per-inch (T6) 1010 Skip to Heading 101 1 Skip to Bottom 1100 Remaining codes may be utilized for ll0l other desired line spacing instructions,

ll 10 such as four spaces at 6-per-inch, and

111 1 six spaces at S-per-inch, etc.

The encoder 94, which as previously mentioned is coupled to the line decoder 90 by a plurality of lines 92, functions to compute the number of l/ inch steps of the stepping motor 16 that will be required to produce the desired line spacing represented by the particular code stored in the line instruction portion of the register 64 and interpreted by the line decoder 90, the computed value being then entered in an adder 96. The following table will serve to reflect the number of H120 inch steps of the stepping motor 16 that will be required to satisfy the various line spacing instructions interpreted by the line decoder 90.

In addition to the register 64, the line decoder 90, the encoder 94 and the adder 96, the previously mentioned means for controllably coordinating the skip and line instructions with the plurality of identifying pulses also includes a field mark counter 76, a field compare unit 70, a step counter 100, a compare unit 98, a motor control unit 66, and a plurality of gates the function of which will be hereinafter described. It is to be noted from FIG. 4 that the field mark counter 76 is coupled to the forms index disk 37 and its associated sensing device 39 by a line 75, and to the field mark disk 26 and its associated sensing device 25 by a line 74, and that the field compare unit 70 is coupled to the field instruction portion of the register 64 by a plurality of lines 68, and coupled also to the field mark counter 76 by lines 78. The step counter 100 is coupled to the motor step disk 18 and its associated sensing device 22 by a plurality of lines 101, an OR gate 104, a line 106, an AND gate 86 and a line 108, and is also coupled to the compare unit 98 by a plurality of lines 99. The compare unit 98 is also coupled to the adder 96 by a plurality of lines (not designated), and to a motor stop and detent control 114 of the motor control 66 by a line 110, an AND gate 84, and an OR gate 112. The field compare unit 70 is also coupled to the motor stop and detent control 114 by a line 80, the AND gate 84 and the OR gate 112. The motor control 66 is further coupled to the motor 16, to an input line 62, and to the sensing device 22 associated with the motor step disk 18 by a plurality of lines 103 and the lines 101. It is also to be noted that the step counter 100 and the adder 96 are coupled to the field mark disk 26 by a line 102, and that the field compare unit 70, in addition to being coupled to the motor stop and detent control 114, is also coupled to the AND gate 86 and the step counter 100 by a line 82.

It can be seen from the above described couplings of the various elements that the field mark counter 76 is reset by each pulse generated by the forms index disk 37 and transmitted along the line 75, and is countably advanced by each pulse generated by the field mark disk 26 and transmitted along the line 74. The step counter 100 and adder 96, on the other hand, are reset by each pulse generated by the field mark disk 26 and transmitted along the line 102, and the step counter 100 is countably advanced by each pulse generated by the motor step disk 18 and photo cells 27 and transmitted along the line 106, when enabled by the AND gate 86. It will be apparent that the field compare unit 70 will function to continuously compare the accumulated count in the field mark counter 76 with the binary coded instruction stored in the field instruction portion of the register 64, and will transmit a signal along the line 80 to the AND gate 84, and along the line 82 to the AND gate 86, whenever an equals state is detected therein. It will also be apparent that the compare unit 98 will function to continuously compare the accumulated count in the step counter 100 with the accumulated value in the adder 96, and will transmit a pulse along the line 110 to the AND gate 84 whenever an equals state is detected therein.

A skip control unit 65 also shown in FIG. 4 is provided to enable slewing or skipping of the web paper 24 in the absence of a field or line instruction code from the central processor along the line 61. A push button switch 63 coupled to the skip control unit 65 is manually operable to activate the stepping motor 16 along the line 62, an input being coincidentally transmitted to the AND gate 118. This manually initiated slewing will terminate when an enabling input signal is transmitted to the AND gate 118 along the line 116, and generated by the forms index disk 37 upon arrival of the gear stack 30 at its home position, a pulse being thus passed to the OR gate 112 and to the motor stop and detent control 114. The AND gate 118 also serves to activate the motor stop and detent control 114 in the normal execution of a Skip to Heading instruction (binary code lOlO stored in the line instruction portion of the register 64), the line decoder in such instance transmitting an input along the line 120 to the AND gate 118, such gate 118 being enabled upon receipt of an input along the line 116 upon arrival of gear stack 30 in its home position, it being apparent that the home positions of the gear stack 30 and the forms index disk 37 would represent the heading of the succeeding form.

OPERATION A full understanding of the operation of the inventive format control system is hereinafter conveyed with reference to FIG. 4, an initial phase of such explanation being of a generalized nature not involving the use of specific skip and line instruction codes, and a subsequent phase thereof describing how representative instruction codes would be utilized to effectuate printing on specified print lines.

it is to be noted before proceeding with this explanation that the field mark counter 76 is reset only at the beginning of each unit of selected form length, when the forms index disk 37 transmits a pulse thereto along the line 75, and that the step counter and adder 96 are reset at the beginning of each A inch increment of paper advancement, when the field mark disk 26 transmits a pulse thereto along the line 120. It is accordingly also to be noted that the field mark counter 76 will accumulatively count a pulse from the disk 26 for each V2 inch print line on the selected form length, and that the step counter 100, when enabled by the AND gate 86, will accumulatively count 60 l/ 120 inches increments of paper advancement between said 5% inch print lines.

Upon setting the dials 36 and 41 (FIG. 1) to select a desired form length (between 8% inches and 17 inches in the preferred embodiment), a pulse is generated by the home positioned form index disk 37 to thereby reset the field mark counter 76, and to transmit an input pulse along the line 116 to the AND gate 118, the step counter 100 and the adder 96 having already been reset by the preceding pulse from the field mark disk 26. Upon receipt of a field instruction code (other than 00000) in the five-digit field instruction portion of the register 64, along the line 61, (and with a 0000 code in the line instruction portion of the register 64) the motor 16 is activated to rotate the motor step disk 18 and the paper advance shaft 12, rotation of the shaft 12 being effective also for rotating the field mark disk 26 and the forms index disk 37. As the field mark disk 26 rotates, the pulses generated by the radial slots therein will be counted by the field mark counter 76, each pulse representing and identifying a A inch increment of paper advancement. It is to be noted that during this advancement of the web paper 24, and counting of the field mark pulses by the counter 76, the pulses generated by the motor step disk 18 will not be counted by the step counter 100, since the AND gate 86 has not been enabled by an input from the field compare unit 70 along the line 82. When the accumulated count in the field mark counter 76 is equal to the five-digit field instruction code in the register 64, the field compare unit 70 will transmit an input pulse along the line 80 to the AND gate 84, such gate 84 also having an input from the compare unit 98 along the line 110 by reason of the O-equals state of the step counter 100 and the adder 96. Upon thus enabling the AND gate 84, a pulse is transmitted through the OR gate 112 to the motor stop and detent control 114 of the motor control 66, the motor 16 being accordingly stopped for printing a line of information on the print line represented by the field instruction code stored in the register 64.

In the event printing is to occur in the first half inch of the selected form length, a line instruction code other than 0000 would be transmitted along the line 61 to the line instruction portion of the register 64 (with a 00000 code in the field instruction portion of the register 64), whereupon the line decoder 90 would serve to activate the selected line 92 corresponding to such line instruction code, the encoder 94 thereupon computing the number of motor steps of U120 inch each that are required to provide the desired line spacing, the value computed being entered in the adder 96. Upon rotational activation of the motor 16, the motor stop pulses generated by the disk 18 and the three photo cells 27 and associated light emitting member 17 would be transmitted along the lines 101, through the OR gate 104, along the line 106 and through the AND gate 86 to the step counter 100, the AND gate 86 having been enabled by an input along the line 82 from the field compare unit 70 by reason of the O-equals state of the field mark counter 76 and the field instruction portion of the register 64. When the count of the step counter 100 is equal to the value entered in the adder 96, the compare unit 98 would transmit an input pulse along the line 110 through the AND gate 84 and the OR gate 1 12 to the motor stop and detent control 114, the AND gate 84 being enabled by the presence of an input along line 80 from the field compare unit 70, also by reason of the O-equals state of the field mark counter 76 and the field instruction portion of the register 64. Upon activation of the motor stop and detent control 114, the motor 16 would be stopped for the printing of the line of information on a print line corresponding to the line instruction code.

To effectuate printing beyond the first half inch of space on a selected form length, and on a print line not corresponding to a 9% inch increment of paper advancement, a field instruction code (other than 00000) and line instruction code (other than 0000) would be transmitted along the line 61 to the register 64, the field instruction code being initially operative to advance the paper 24 to the print line corresponding to the /2 inch increment next preceding the the desired print line, and the line instruction code being thereafter effective, without stopping the motor 16, to advance the paper 24 from such preceding k inch increment line to the desired print line. Upon receipt of the spacing codes in the register 64, the line decoder 90 would be responsive to the line instruction code to activate a selected line 92 to the encoder 94, the encoder 94 thereupon computing the number of [[120 inch motor steps required to advance the paper 24 from the IQ inch increment line corresponding to the entered field instruction code to the desired print line, such value being entered in the adder 96. At the outset of motor activation, the step counter 100 would be in a reset state by reason of the preceding pulse generated by the field mark disk 26, and the field mark counter 76 would contain an accumulated count corresponding to the recorded /2 inch increments of previous paper advancement. Since the field instruction code stored in the five-digit field instruction portion of the register 64 would be of higher value than the accumulated count in the field mark counter 76, the AND gate 86 would not initially be provided with an input along the lines 80 and 82 from the field compare unit 70, and the motor step pulses generated by the disk 18 would initially be blocked from the step counter 100. It can thus be seen that during the early stage of motor activation, only the pulses generated by the field mark disk 26 would be counted (by the field mark counter 76), an enabling pulse being transmitted by the field compare unit along the line 82 to the AND gate 86 when an equals state is detected therein, the AND gate 86 being thus enabled to pass the subsequently generated pulses from the motor step disk 18 to the step counter 100 where they would then be counted. When the count of the motor step pulses equals the value stored in the adder 96, to represent the arrival of the desired print line, the compare unit 98 would transmit a pulse along the line 110 through the AND gate 84 and OR gate 112 to the motor stop and detent control 114, the AND gate 84 having also been enabled by the previously mentioned pulse from the field compare unit 70, along line 80. The motor 16 would accordingly be stopped at the desired print line for the printing of a line of information.

The following explanation is set forth to illustrate how various field instruction codes and line instruction codes would be utilized in the inventive tapeless form at control system to effectuate printing on desired print lines on a selected form length. With the form select dial 41 set on the 14 inches mark as shown in FIG. 5, printing on various lines on a 14 inch form may be explained with reference to FIG. 6. If after setting the dial 41 on the 14 inch mark, it is then desired to print a first line of information on the 5 inch line of the form, the field instruction code 01010 would be entered in the five-digit field instruction portion of the register 64, and the code 0000 entered in the line instruction portion of the register 64. During the resultant activation of the motor 16, the field instruction portion of the register 64 being greater than the count in the field mark counter 76, the AND gate 86 would not be enabled by an input along the line 82 to permit the step counter 100 to count the motor pulses generated by the disk 18, paper advancement continuing until the count in the field mark counter 76 is equal to the field instruction code (in this case both equaling 10), whereupon the field compare unit 70 would transmit a pulse along the line through the AND gate 84 to the motor stop and detent control 114, the AND gate 84 being enabled by an input from the compare unit 98 along the line 110 by reason of the O-equals state of the step counter 100 and the adder 96. Paper advancement would accordingly terminate with the 5 inch line of the form in printing position.

If after printing the line of information on the 5 inch line, it were then desired to print four lines of information in S10 spacing immediately following the 5 inch line, the codes 01010 and 0001 would be entered in the field instruction and line instruction portions, respectively, of the register 64 for each of the desired four lines of printing. With the OOOl code in the line instruction portion of the register 64, the line decoder 90 would activate the 510 line 92 to the encoder 94, whereupon the encoder 94 would compute and transmit to adder 96 a different value for each of the four lines of printing, such values, representing the accumulated number of U120 inch motor steps required to produce each of the four lines of S10 spacing, being 12, 24, 36 and 48, respectively. With the field mark counter 76 and the field instruction portion of the register 64 both being in a IO-equals state, the AND gate 86 would be enabled for each line of printing by an input from the field compare unit 70 along the lines 80 and 82, to thereby enable the passage of the motor step pulses from the disk 18 to the step counter 100. Upon the counting of 12, 24, 36 and 48 motor step pulses, respectively, for the respective lines of printing, the compare unit 98 would transmit a pulse along the line 110 through the AND gate 84 and OR gate 112 to the motor stop and detent control 114, the AND gate 84 also having been enabled by the previously mentioned pulse from the field compare unit 70.

lf after printing the four lines of information in 810 spacing immediately following the inch line, it were then desired to print two lines of information in D spacing immediately following the 7 inch line on the form, the codes 01110 and 0100 would be entered in the field instruction and line instruction portions, respectively, of the register 64 for each of the desired two lines of printing, entry of the 011 10 code for the first line of printing creating an unequal state between the field mark counter 76 and the field instruction portion of the register 64, and entry of the code 0100 for each of the two lines causing the line decoder 90 to activate the D10 line 92 to the encoder 94, the encoder 94 thereupon computing and entering in the adder 96 a value of 24 for the first line of printing and a value of 48 for the second line, such values representing the accumulated number of motor steps required to produce each of the two lines of printing. in view of the unequal state of the field mark counter 76 and the field instruction portion of the register 64 during spacing for the first line, the motor step pulses from the disk 18 would initially be blocked from the step counter 100 by the AND gate 86, and four pulses generated by the field mark disk 26 would be counted by the field mark counter 76 (corresponding to the 5%, 6, 672 and 7 inch lines on the form). Upon the occurrence ofa l4-equals state of the field mark counter 76 and the field instruction portion of the register 64 a pulse would be transmitted from the field compare unit 70 along the line 80 to the AND gate 84, and along the line 82 to the AND gate 86, the AND gate 84 not being enabled by an input from the compare unit 98 due to the unequal state of the adder 96 and the step counter 100, the gate 86, however, being enabled by such pulse to permit the passage of motor step pulses from the disk 18 to the step counter 100. Upon the counting of 24 motor step pulses by the counter 100, the compare unit 98 would transmit a pulse along the line 110 through the AND gate 84 and OR gate 112 to the motor stop and detent control 114, the AND gate 84 being enabled by the previously mentioned input from the field compare unit 70. Advancement of the paper 24 would accordingly be terminated for the printing of the first line of information following the 7 inch line. The codes 01110 and 0100 would then be entered in the field instruction and line instruction portions, respectively, of the register 64 for the printing of the second line of information in D10 spacing, an enabling pulse from the field compare unit being immediately transmitted to the AND gates 84 and 86, by reason of the l4-equals state of the field mark counter 76 and the field instruction portion of the register 64, the motor step pulses from the disk 18 being accordingly passed through the AND gate 86 and counted by the step counter 100. Upon the occurrence of a 48-equals state in the step counter and the adder 96 (representing the accumulated counts therein, respectively), the compare unit 98 would transmit a pulse along the line through the enabled AND gate 84 to the motor stop and detent control 114, to thereby terminate paper advancement for the printing of the second line of information in D10 spacing.

If after printing the two lines of information in D10 spacing immediately following the 7 inch line on the form, it were then desired to print two lines of information in S8 spacing immediately following the 8 inch line, the codes 10000 and 0010 would be entered in the field instruction and line instruction portions, respectively, of the register 64 for each of the two lines of printing, spacing for the first line of printing involving the initial counting of two pulses from the field mark disk 26 by the counter 76 (corresponding to the 7% and 8 inch lines), and the subsequent counting of 15 motor step pulses from the disk 18 by the step counter 100 (to create a lS-equals state in the step counter 100 and adder 96), when a l6-equals state occurs in the field mark counter 76 and the field instruction portion of the register 64, as previously described. Upon entering the codes 10000 and 0010 for the second line of S8 printing, the AND gate 86 would be enabled immediately by an input along the line 82 resulting from the l6-equals state of the field mark counter 76 and the field instruction portion of the register 64, the step counter 100 proceeding to count the motor step pulses from the disk 18. Upon the counting of 15 additional motor step pulses by the counter 100, to present an accumulated count of 30 therein (such being the value computed by the encoder 94 and stored in the adder 96 upon entry of the code 0010 for the second line of printing), a pulse would be transmitted from the compare unit 98 along the line 110 through the enabled AND gate 84 to the motor stop and detent control 114, to thereby terminate paper advancement for the printing of the second line of information in S8 spacing.

If after printing the two lines of information in S8 spacing immediately following the 8 inch line on the form, it were then desired to print one line of information on the 13 inch line and one line of information in T6 spacing immediately following the 13 inch line, the codes 1 1010 and 0000 would be entered in the field instruction and line instruction portions, respectively, of the register 64 for printing on the 13 inch line, and the codes 1 1010 and 1001 would be entered in the respective portions of the register 64 for the printing of the second line in T6 spacing. Entry of the l 1010 and 0000 codes would result immediately in the transmission of an input pulse from the compare unit 98 to the AND gate 84, by reason of the O-equals state of the step counter 100 and adder 96, the field mark counter 76 proceeding to count ten pulses from the field mark disk 26 (corresponding to the 8V2, 9, 9 /2, 10 10%, ll, 11%, 12, 12% and 13 inch lines on the form), and the field compare unit 70 serving to transmit a pulse to the AND gate 84 upon the occurrence of a 26-equals state in the field mark counter 76 and the field instruction portion of the register 64, the AND gate 84 being thereby enabled to pass a pulse through the OR gate 112 to the motor stop and detent control 114 to terminate paper advancement for the printing of the line of information on the 13 inch line of the form. Upon the entry of the l 1010 and lOOl codes in the respective portions of the register 64, for the printing of the second line of information in T6 spacing, the AND gate 86 would immediately receive an input along the line 82 from the field compare unit 70, due to the 26-equals state of the field mark counter 76 and the field instruction portion of the register 64, the step counter 100 being thereby rendered enabled to count the motor step pulses from the disk 18. Upon the counting of 60 motor step pulses by the counter 100, such being the value computed by the encoder 94 and entered in the adder 96 upon activation of the T6 line 92 by the line decoder 90, a pulse would be generated by the compare unit 98 and transmitted along the line 110 through the enabled AND gate 84 to the motor stop and detent control 114, to thereby terminate paper advancement for the printing of the second line in T6 spacing.

While the preferred embodiment of the tapeless format control system has been described herein in considerable detail, it will be appreciated that various modifications and alterations therein may be conceived by persons skilled in the art without departing from the true spirit and scope of the invention.

What is claimed is:

1. A tapeless format control apparatus for selectively advancing web paper in a line printer, said line printer having web paper handling and positioning means associated with a printing position thereof, said apparatus comprising:

a. a stepping motor for operatively advancing said web paper relative to said printing position, said stepping motor being coupled to said web paper handling and positioning means,

motor control means associated with said stepping motor and effective fot stopping and detenting said stepping motor,

c. means for selectively determining the length of the web paper upon which lines of information are to be printed, to thereby constitute a selected form length, said web paper length determining means comprising:

a plurality of gears of varying diameters fixed to a rotatable first shaft in coaxial relationship to form a conical gear stack, each of said gears of said stack representing a different form length; an elongated cylindrical gear coupled to said web paper handling and positioning means of said line printer; and adjustable means for coupling said elongated cylindrical gear with a selected one of said plurality of gears forming said conical gear stack, said adjustable coupling means comprisa translatably supported toothed rack disposed intemediate and in parallel relationship relative to said elongated cylindrical gear and said conical gear stack; an idling coupling gear rotatably mounted on the innermost extremity of said toothed rack, said coupling gear being engageably disposed relative to said elongated cylindrical gear and individual ones of said plurality of gears forming said conical gear stack; and means responsive to manual manipulation for selectively translating said toothed rack and said coupling gear relative to said elongated cylindrical gear so as to cooperably couple a selected gear of said conical gear stack with said elongated cylindrical gear, d. means for receiving and storing externally originated print spacing instructions, e. a plurality of pulse generating means including first pulsing means for identifying each increment of advancement of said web paper, second pulsing means for identifying each increment of rotational motion of said stepping motor, and third pulsing means for identifying the passage of each unit of selected form length, and means cooperating with said motor control means and responsive to said externally originated print spacing instructions for controllably coordinating the pulses generated by said plurality of pulse generating means such that each line of information printed on said selected form length is properly spaced from the preceding line and all of the lines of printed information conform to a preselected format represented by said externally originated print spacing instructions.

2. The format control apparatus defined in claim 1 wherein said means for selectively translating said toothed rack and said coupling gear comprises:

a. a pinion gear rotatably mounted on a rotatable second shaft in engaged relationship with the teeth of said toothed rack,

b. a third shaft gearably coupled to said second shaft,

and

c. a manually manipulatable dial member fixed to said third shaft at the end thereof opposite the end gearably coupled to said second shaft.

3. The format control apparatus defined in claim 1 wherein said means for receiving and storing said externally originated print spacing instructions comprises:

a. a shaft register having a field skip portion for temporarily storing a binary decimal code indicative of the number of increments of web paper advancement that are required in an initial skipping phase thereof, and a line advance portion for storing a binary decimal code indicative of the number of increments of rotational motion of the stepping motor that are required in a line advance phase of said web paper advancement.

4. The format control apparatus defined in claim 3 wherein said first pulsing means for identifying each increment of advancement of said web paper comprises:

a. a first multi-slotted disk coupled to said web paper handling and positioning means in contiguous relationship with said elongated cylindrical gear, and

b. a first sensing device comprised of a light emitting member and a light sensitive switch, said first sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said first multi-slotted disk.

5. The format control apparatus defined in claim 4 wherein said second pulsing means for identifying each increment of rotational motion of said stepping motor comprises:

a. a second multi-slotted disk coupled to a motor shaft of said stepping motor, and

b. a second sensing device comprised of at least one light emitting member and at least one light sensitive switch. said second sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said second multi slotted disk.

6. The format control apparatus defined in claim wherein said third pulsing means for identifying the passage of each unit of selected form length comprises:

a. a third slotted disk coupled to said first shaft at an extremity thereof adjacent said conical gear stack, and

b. a third sensing device comprised of a light emitting member and a light sensitive switch, said third sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said third slotted disk.

7. The format control apparatus defined in claim 4 wherein said first multi-slotted disk is provided with l6 radially disposed and equally spaced-apart slots, the movement of each slot into cooperating relationship with said first sensing device representing a /2 inch increment of web paper advancement.

8. The format control apparatus defined in claim 5 wherein said second multi-slotted disk is provided with eight radially disposed and equally spaced-apart slots and said second sensing device is provided with three serially arranged light emitting members and light sensitive switches, the movement of each of said slots into cooperating relationship with each of said three serially arranged light emitting members and light sensitive switches representing a angular displacement of said stepping motor as translated into a 1/120 inch increment of web paper advancement.

9. The format control apparatus defined in claim 6 wherein said third slotted disk is provided with a single radially disposed slot the movement thereof into cooperating relationship with said third sensing device representing the passage of each unit of selected form length as delineated by said adjustable means of said web paper length determining means.

10. The format control apparatus defined in claim 6 wherein said means for controllably coordinating said pulses generated by said plurality of pulse generating means comprises:

a. first counter means associated with said first and said third slotted disks and with said first and third sensing devices,

b. first comparator means operatively coupled to said first counter means and to said field skip portion of said shift register,

e. value determining means associated with and cou' pled to said line advance portion of said shift register, said valve determining means including a value store,

d. second counter means associated with said first and second slotted disks and with said first and second sensing devices,

e. second comparator means operatively coupled to said second counter means and to said value store,

f. first gating means coupled to said first and said second comparator means and effective for outputting a pulse to said motor control means to thereby stop said stepping motor when an equals state is detected by both said first and second comparator means, and

g. second gating means coupled to said second sensing device and to said first comparator means and effective for outputting pulses generated by said second sensing device and said second slotted disk to said second counter means upon receipt of an enabling pulse from said first comparator means.

11. The format control apparatus defined in claim 10 wherein said value determining means additionally comprises:

a. a decoder coupled to said line advance portion of said shift register and effective for decoding a binary coded signal stored therein to thereby activate a selected one of a plurality of output channels corresponding to said binary coded signal, said binary coded signal being representative of a predetermined line advance instruction, and

b. an encoder coupled to said decoder by means of said plurality of output channels and coupled also to said value store, said encoder being effective for computing a value representative of the number of incremental motor steps required to execute said predetermined line advance instruction and to enter said value in said value store.

12. The format control apparatus defined in claim 11 wherein said means for controllably coordinating said pulses generated by said plurality of pulse generating means additionally comprises: third gating means coupled to said third sensing device and to said decoder by means of a predetermined one of said output channels thereof, said third gating means being coupled also to a manually operable skip control unit effective for advancing said web paper in the absence of a binary coded signal in either said field skip or line advance portions of said shift register, enabling of said third gating means by a pulse generated by said third slotted disk and said third sensing device and a pulse from either said skip control unit or said decoder being effec tive to output a signal to said motor control means to thereby stop said stepping motor.

13. The format control apparatus defined in claim 12 wherein said first, said second, and said third gating means are AND gates.

14. In a line printer having a transport apparatus for advancing and positioning a web medium relative to a print station, a format control system for controlling the transport apparatus in response to web medium spacing instructions communicated to the printer, comprising:

a. a stepping motor coupled to said transport apparatus and effective for advancing the web medium in a controlled stepping manner,

b. a shift register for storing in binary coded form, ex-

ternally originated print spacing instructions, said shift register having a field skip portion for storing a binary coded instruction indicative of the number of predetermined increments of web medium advancement that are required in an initial course positioning thereof, and a line advance portion for storing a binary coded instruction indicative of the number of lines per measured distance that are to be skipped during an ensuing fine positioning of the web medium, said coarse and fine positioning being effective to advance the web medium to a print position corresponding to said externally originated print spacing instructions,

c. first pulse generating means for outputting a signal upon sensing each increment of web medium advancement, each of said increments of web medium advancement being of a predetermined first order of magnitude.

d. second pulse generating means for outputting a signal upon sensing each increment of rotational motion of said stepping motor, to thereby represent a corresponding increment of web medium advancement, each of said increments of web medium advancement being of a predetermined second order of magnitude,

e. third pulse generating means for measuring and outputting a signal upon sensing that a predetermined length of the web medium has been advanced, said predetermined length constituting a predetermined form length,

f. means for selectively determining the length of the web medium upon which lines of information are to be printed, to thereby constitute a selected form length as measured by said third pulse generating means, said web medium length determining means comprising:

a plurality of gears of varying diameters fixed to a rotatable first shaft in coaxial relationship to form a conical gear stack, each of said plurality of gears of said conical gear stack representing a different form length; an elongated cylindrical gear coupled to said transport apparatus of said line printer; and adjustable means for coupling said elongated cylindrical gear with a selected one of said plurality of gears forming said conical gear stack, said adjustable coupling means comprising:

a translatably supported toothed rack disposed intermediate and in parallel relationship relative to said elongated cylindrical gear and said conical gear stack; an idling coupling gear rotatably mounted on the innermost extremity of said toothed rack, said coupling gear being engageably disposed relative to said elongated cylindrical gear and individual ones of said plurality of gears forming said conical gear stack; and means responsive to manual manipulation for selectively translating said toothed rack and said coupling gear relative to said elongated cylindrical gear so as to cooperably couple a selected gear of said conical gear stack with said elongated cylindrical gear, and

g. means cooperating with said stepping motor and response to said externally originated print spacing instructions stored in said shift register for controllably coordinating said signals generated by said first, said second and said third pulse generating means such that each line of information printed on said predetermined form length is properly spaced from the preceding lines and all of the lines of printed information conform to a preselected format represented by said externally originated print spacing instructions.

15. The format control system defined in claim 14 wherein said means for selectively translating said toothed rack and said coupling gear comprises:

a. a pinion gear rotatably mounted on a rotatable second shaft in engaged relationship with the teeth of said toothed rack,

b. a third shaft gearably coupled to said second shaft,

and

c. a manually manipulatable dial member fixed to said third shaft at the end thereof opposite the end gearably coupled to said second shaft.

16. The format control system defined in claim 14 wherein said means for controllably coordinating said signals generated by said first, said second, and said third pulse generating means comprises:

a. a first counter associated with said first and said third pulse generating means,

b. a first comparator operatively coupled to said first counter and to said field skip portion of said shift register,

c. valve determining means associated with and coupled to said line advance portion of said shift register, said value determining means including a value storing adder,

d. a second counter associated with said first and said second pulse generating means,

e. a second comparator operatively coupled to said second counter and to said value storing adder,

f. first gating means coupled to said first and said second comparators and effective for outputting a signal to said stepping motor to thereby stop said stepping motor when an equals state is detected in both said first and second comparators, and

g. second gating means coupled to said second pulse generating means and to said first comparator and effective for outputting pulses generated by said second pulse generating means to said second counter upon receipt of an enabling signal from said first comparator.

17. The format control system defined in claim 16 wherein said value determining means additionally comprises:

a. a decoder coupled to said line advance portion of said shift register and effective for decoding a binary coded signal stored therein to thereby activate a selected one of a plurality of output channels corresponding to said binary coded signal, said binary coded signal being representative of a predetermined line advance instruction, and

b. an encoder coupled to said decoder by means of said plurality of output channels and coupled also to said value storing adder, said encoder being effective for computing a value representative of the number of incremental motor steps required to ex ecute said predetermined line advance instruction and to enter said value in said value storing adder.

18. The format control system defined in claim 17 wherein said means for controllably coordinating the signals generated by said first, said second and said third pulse generating means additionally comprises: third gating means coupled to said third pulse generating means and to said decoder by means of a predetermined one of said output channels thereof, said third gating means being coupled also to a manually operable skip control unit effective for advancing said web medium in the absence of a binary coded instruction in either said field skip or line advance portions of said shift register, enabling of said third gating means by a pulse generated by said third pulse generating means and a pulse from either said skip control unit or said decoder being effective to output a signal to said stepping motor to thereby stop said stepping motor.

19. The format control system defined in claim 18 wherein said first, said second, and said third gating means are AND gates.

20. The format control system defined in claim 14 wherein said third pulse generating means comprises:

a. a slotted disk coupled to said first shaft at an extremity thereof adjacent said conical gear stack,

and

b. a sensing device comprised of a light emitting member and a light sensitive switch said sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said slotted disk.

21. The format control system defined in claim 14 wherein said first pulse generating means comprises:

a. a first multi-slotted disk coupled to said transport apparatus in contiguous relationship with said elongated cylindrical gear, and

b. a sensing device comprised of a light emitting member and a light sensitive switch, said sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said first multi-slotted disk 22. The format control system defined in claim 21 wherein said second pulse generating means comprises:

a. a second multi-slotted disk coupled to a motor shaft of said stepping motor, and

b. a second sensing device comprised of at least one light emitting member and at least one light sensitive switch, said second sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said second multislotted disk.

23. The format control system defined in claim 20 wherein said slotted disk of said third pulse generating means is provided with a single radially disposed slot the movement thereof into cooperating relationship with said sensing device representing the passage of each unit of selected form length as delineated by said adjustable means of said web medium length determin' ing means.

24. The format control system defined in claim 21 wherein said first multi-slotted disk of said first pulse generating means is provided with 16 radially disposed and equally spaced-apart slots, the movement of each slot into cooperating relationship with said sensing device representing a k inch increment of web medium advancement 25. The format control system defined in claim 22 wherein said second multi slotted disk of said second pulse generating means is provided with eight radially disposed and equally spaced-apart slots and said second sensing device of said second pulse generating means is provided with three serially arranged light emitting members and light sensitive switches, the movement of each of said slots into cooperating relationship with each of said light emitting members and light sensitive switches representing a l5 angular displacement of said stepping motor as translated into a 1/120 inch increment of web medium advancement. 

1. A tapeless format control apparatus for selectively advancing web paper in a line printer, said line printer having web paper handling and positioning means associated with a printing position thereof, said apparatus comprising: a. a stepping motor for operatively advancing said web paper relative to said printing position, said stepping motor being coupled to said web paper handling and positioning means, b. motor control means associated with said stepping motor and effective fot stopping and detenting said stepping motor, c. means for selectively determining the length of the web paper upon which lines of information are to be printed, to thereby constitute a selected form length, said web paper length determining means comprising: a plurality of gears of varying diameters fixed to a rotatable first shaft in coaxial relationship to form a conical gear stack, each of said gears of said stack representing a different form length; an elongated cylindrical gear coupled to said web paper handling and positioning means of said line printer; and adjustable means for coupling said elongated cylindrical gear with a selected one of said plurality of gears forming said conical gear stack, said adjustable coupling means comprising: a translatably supported toothed rack disposed intemediate and in parallel relationship relative to said elongated cylindrical gear and said conical gear stack; an idling coupling gear rotatably mounted on the innermost extremity of said toothed rack, said coupling gear being engageably disposed relative to said elongated cylindrical gear and individual ones of said plurality of gears forming said conical gear stack; and means responsive to manual manipulation for selectively translating said toothed rack and said coupling gear relative to said elongated cylindrical gear so as to cooperably couple a selected gear of said conical gear stack with said elongated cylindrical gear, d. means for receiving and storing externally originated print spacing instructions, e. a plurality of pulse generating means including first pulsing means for identifying each increment of advancement of said web paper, second pulsing means for identifying each increment of rotational motion of said stepping motor, and third pulsing means for identifying the passage of each unit of selected form length, and f. means cooperating with said motor control means and responsive to said externally originated print spacing instructions for controllably coordinating the pulses generated by said plurality of pulse generating means such that each line of information printed on said selected form length is properly spaced from the preceding line and all of the lines of printed information conform to a preselected format represented by said externally originated print spacing instructions.
 2. The format control apparatus defined in claim 1 wherein said means for selectively translating said toothed rack and said coupling gear comprises: a. a pinion gear rotatably mounted on a rotatable second shaft in engaged relationship with the teeth of said toothed rack, b. a third shaft gearably coupled to said second shaft, and c. a manually manipulatable dial member fixed to said third shaft at the end thereof opposite the end gearably coupled to said second shaft.
 3. The format control apparatus defined in claim 1 wherein said means for receiving and storing said externally originated print spacing instructions comprises: a. a shaft register having a field skip portion for temporarily storing a binary decimal code indicative of the number of increments of web paper advancement that are required in an initial skipping phase thereof, and a line advance portion for storing a binary decimal code indicative of the number of increments of rotational motion of the stepping motor that are required in a line advance phase of said web paper advancement.
 4. The format control apparatus defined in claim 3 wherein said first pulsing means for identifying each increment of advancement of said web paper comprises: a. a first multi-slotted disk coupled to said web paper handling and positioning means in contiguous relationship with said elongated cylindrical gear, and b. a first sensing device comprised of a light emitting member and a light sensitive switch, said first sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said first multi-slotted disk.
 5. The format control apparatus defined in claim 4 wherein said second pulsing means for identifying each increment of rotational motion of said stepping motor comprises: a. a second multi-slotted disk coupled to a motor shaft of said stepping motor, and b. a second sensing device comprised of at least one light emitting member and at least one light sensitive switch, said second sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said second multi-slotted disk.
 6. The format control apparatus defined in claim 5 wherein said third pulsing means for identifying the passage of each unit of selected form length comprises: a. a third slotted disk coupled to said first shaft at an extremity thereof adjacent said conical gear stack, and b. a third sensing device comprised of a light emitting member and a light sensitive switch, said third sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said third slotted disk.
 7. The format control apparatus defined in claim 4 wherein said first multi-slotted disk is provided with 16 radially disposed and equally spaced-apart slots, the movement of each slot into cooperating relationship with said first sensing device representing a 1/2 inch increment of web paper advancement.
 8. The format control apparatus defined in claim 5 wherein said second multi-slotted disk is Provided with eight radially disposed and equally spaced-apart slots and said second sensing device is provided with three serially arranged light emitting members and light sensitive switches, the movement of each of said slots into cooperating relationship with each of said three serially arranged light emitting members and light sensitive switches representing a 15* angular displacement of said stepping motor as translated into a 1/120 inch increment of web paper advancement.
 9. The format control apparatus defined in claim 6 wherein said third slotted disk is provided with a single radially disposed slot the movement thereof into cooperating relationship with said third sensing device representing the passage of each unit of selected form length as delineated by said adjustable means of said web paper length determining means.
 10. The format control apparatus defined in claim 6 wherein said means for controllably coordinating said pulses generated by said plurality of pulse generating means comprises: a. first counter means associated with said first and said third slotted disks and with said first and third sensing devices, b. first comparator means operatively coupled to said first counter means and to said field skip portion of said shift register, c. value determining means associated with and coupled to said line advance portion of said shift register, said valve determining means including a value store, d. second counter means associated with said first and second slotted disks and with said first and second sensing devices, e. second comparator means operatively coupled to said second counter means and to said value store, f. first gating means coupled to said first and said second comparator means and effective for outputting a pulse to said motor control means to thereby stop said stepping motor when an equals state is detected by both said first and second comparator means, and g. second gating means coupled to said second sensing device and to said first comparator means and effective for outputting pulses generated by said second sensing device and said second slotted disk to said second counter means upon receipt of an enabling pulse from said first comparator means.
 11. The format control apparatus defined in claim 10 wherein said value determining means additionally comprises: a. a decoder coupled to said line advance portion of said shift register and effective for decoding a binary coded signal stored therein to thereby activate a selected one of a plurality of output channels corresponding to said binary coded signal, said binary coded signal being representative of a predetermined line advance instruction, and b. an encoder coupled to said decoder by means of said plurality of output channels and coupled also to said value store, said encoder being effective for computing a value representative of the number of incremental motor steps required to execute said predetermined line advance instruction and to enter said value in said value store.
 12. The format control apparatus defined in claim 11 wherein said means for controllably coordinating said pulses generated by said plurality of pulse generating means additionally comprises: third gating means coupled to said third sensing device and to said decoder by means of a predetermined one of said output channels thereof, said third gating means being coupled also to a manually operable skip control unit effective for advancing said web paper in the absence of a binary coded signal in either said field skip or line advance portions of said shift register, enabling of said third gating means by a pulse generated by said third slotted disk and said third sensing device and a pulse from either said skip control unit or said decoder being effective to output a signal to said motor control means to thereby stop said stepping motor.
 13. The format control apparatus defined in claim 12 wherein said first, said second, and said thIrd gating means are AND gates.
 14. In a line printer having a transport apparatus for advancing and positioning a web medium relative to a print station, a format control system for controlling the transport apparatus in response to web medium spacing instructions communicated to the printer, comprising: a. a stepping motor coupled to said transport apparatus and effective for advancing the web medium in a controlled stepping manner, b. a shift register for storing in binary coded form, externally originated print spacing instructions, said shift register having a field skip portion for storing a binary coded instruction indicative of the number of predetermined increments of web medium advancement that are required in an initial course positioning thereof, and a line advance portion for storing a binary coded instruction indicative of the number of lines per measured distance that are to be skipped during an ensuing fine positioning of the web medium, said coarse and fine positioning being effective to advance the web medium to a print position corresponding to said externally originated print spacing instructions, c. first pulse generating means for outputting a signal upon sensing each increment of web medium advancement, each of said increments of web medium advancement being of a predetermined first order of magnitude, d. second pulse generating means for outputting a signal upon sensing each increment of rotational motion of said stepping motor, to thereby represent a corresponding increment of web medium advancement, each of said increments of web medium advancement being of a predetermined second order of magnitude, e. third pulse generating means for measuring and outputting a signal upon sensing that a predetermined length of the web medium has been advanced, said predetermined length constituting a predetermined form length, f. means for selectively determining the length of the web medium upon which lines of information are to be printed, to thereby constitute a selected form length as measured by said third pulse generating means, said web medium length determining means comprising: a plurality of gears of varying diameters fixed to a rotatable first shaft in coaxial relationship to form a conical gear stack, each of said plurality of gears of said conical gear stack representing a different form length; an elongated cylindrical gear coupled to said transport apparatus of said line printer; and adjustable means for coupling said elongated cylindrical gear with a selected one of said plurality of gears forming said conical gear stack, said adjustable coupling means comprising: a translatably supported toothed rack disposed intermediate and in parallel relationship relative to said elongated cylindrical gear and said conical gear stack; an idling coupling gear rotatably mounted on the innermost extremity of said toothed rack, said coupling gear being engageably disposed relative to said elongated cylindrical gear and individual ones of said plurality of gears forming said conical gear stack; and means responsive to manual manipulation for selectively translating said toothed rack and said coupling gear relative to said elongated cylindrical gear so as to cooperably couple a selected gear of said conical gear stack with said elongated cylindrical gear, and g. means cooperating with said stepping motor and response to said externally originated print spacing instructions stored in said shift register for controllably coordinating said signals generated by said first, said second and said third pulse generating means such that each line of information printed on said predetermined form length is properly spaced from the preceding lines and all of the lines of printed information conform to a preselected format represented by said externally originated print spacing instructions.
 15. The format control system defined in claim 14 wherein said means for selectively translating said toothed rack and said coupliNg gear comprises: a. a pinion gear rotatably mounted on a rotatable second shaft in engaged relationship with the teeth of said toothed rack, b. a third shaft gearably coupled to said second shaft, and c. a manually manipulatable dial member fixed to said third shaft at the end thereof opposite the end gearably coupled to said second shaft.
 16. The format control system defined in claim 14 wherein said means for controllably coordinating said signals generated by said first, said second, and said third pulse generating means comprises: a. a first counter associated with said first and said third pulse generating means, b. a first comparator operatively coupled to said first counter and to said field skip portion of said shift register, c. valve determining means associated with and coupled to said line advance portion of said shift register, said value determining means including a value storing adder, d. a second counter associated with said first and said second pulse generating means, e. a second comparator operatively coupled to said second counter and to said value storing adder, f. first gating means coupled to said first and said second comparators and effective for outputting a signal to said stepping motor to thereby stop said stepping motor when an equals state is detected in both said first and second comparators, and g. second gating means coupled to said second pulse generating means and to said first comparator and effective for outputting pulses generated by said second pulse generating means to said second counter upon receipt of an enabling signal from said first comparator.
 17. The format control system defined in claim 16 wherein said value determining means additionally comprises: a. a decoder coupled to said line advance portion of said shift register and effective for decoding a binary coded signal stored therein to thereby activate a selected one of a plurality of output channels corresponding to said binary coded signal, said binary coded signal being representative of a predetermined line advance instruction, and b. an encoder coupled to said decoder by means of said plurality of output channels and coupled also to said value storing adder, said encoder being effective for computing a value representative of the number of incremental motor steps required to execute said predetermined line advance instruction and to enter said value in said value storing adder.
 18. The format control system defined in claim 17 wherein said means for controllably coordinating the signals generated by said first, said second and said third pulse generating means additionally comprises: third gating means coupled to said third pulse generating means and to said decoder by means of a predetermined one of said output channels thereof, said third gating means being coupled also to a manually operable skip control unit effective for advancing said web medium in the absence of a binary coded instruction in either said field skip or line advance portions of said shift register, enabling of said third gating means by a pulse generated by said third pulse generating means and a pulse from either said skip control unit or said decoder being effective to output a signal to said stepping motor to thereby stop said stepping motor.
 19. The format control system defined in claim 18 wherein said first, said second, and said third gating means are AND gates.
 20. The format control system defined in claim 14 wherein said third pulse generating means comprises: a. a slotted disk coupled to said first shaft at an extremity thereof adjacent said conical gear stack, and b. a sensing device comprised of a light emitting member and a light sensitive switch, said sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said slotted disk.
 21. The format control system defined in claim 14 wherein said first pulse generating means comprises: a. a first multi-slotted disk coupled to said transport apparatus in contiguous relationship with said elongated cylindrical gear, and b. a sensing device comprised of a light emitting member and a light sensitive switch, said sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said first multi-slotted disk.
 22. The format control system defined in claim 21 wherein said second pulse generating means comprises: a. a second multi-slotted disk coupled to a motor shaft of said stepping motor, and b. a second sensing device comprised of at least one light emitting member and at least one light sensitive switch, said second sensing device being coupled to said pulse coordinating means and disposed in cooperating relationship with said second multi-slotted disk.
 23. The format control system defined in claim 20 wherein said slotted disk of said third pulse generating means is provided with a single radially disposed slot the movement thereof into cooperating relationship with said sensing device representing the passage of each unit of selected form length as delineated by said adjustable means of said web medium length determining means.
 24. The format control system defined in claim 21 wherein said first multi-slotted disk of said first pulse generating means is provided with 16 radially disposed and equally spaced-apart slots, the movement of each slot into cooperating relationship with said sensing device representing a 1/2 inch increment of web medium advancement.
 25. The format control system defined in claim 22 wherein said second multi-slotted disk of said second pulse generating means is provided with eight radially disposed and equally spaced-apart slots and said second sensing device of said second pulse generating means is provided with three serially arranged light emitting members and light sensitive switches, the movement of each of said slots into cooperating relationship with each of said light emitting members and light sensitive switches representing a 15* angular displacement of said stepping motor as translated into a 1/120 inch increment of web medium advancement. 